Pollination of Pecans 



99 



floral 



or partially dependent on other varieties for their necessary 

 amount of pollen. 



These two groups are easily distinguished by the 

 characters of the catkins of staminate 

 flowers and also by the difference in devel- 

 opment of the pollen-grains. In the first 

 group the embryonic catkins of staminate 

 flowers are inclosed in rather short broad 

 bud-scales, one on each side of the leaf-bud. 

 The catkins themselves are rather short 

 when their length is compared with their 

 thickness, and the individual flowers are 

 shielded by short rather small and in- 

 conspicuous bracts. The catkins protrude 

 from the bud-scales from one to five 

 days before those of the second group. In 

 most of the varieties the pistillate flowers 

 become receptive at about the same time 

 that the staminate flowers shed their pollen. 

 A few kinds of this group, however, have a 

 considerable percentage of their pistillate 

 flowers receptive after the maximum dehi- 

 scence of pollen (see Fig. 22). 



In the second group the embryonic cat- 

 kins of staminate flowers are inclosed in 

 long and rather slender bud-scales. These 

 catkins are usually narrower and longer 

 than those of the first group and the individual flowers are 

 shielded by long narrow conspicuous bracts. The pistillate 

 flowers become receptive from two to ten days before the 

 staminate shed their pollen ; and in most cases a large per- 



Figure 22.— Pe- 

 can twigs showing 

 the two groups of 

 varieties in bud 

 stage. Twig on 

 left from group /; 

 twig on right from 

 group //. Note how 

 the catkins of 

 group / protrude 

 while the buds are 

 still small. 



